Figure 3 - full size



	Figure 3 - full size

Figure 3.
Fig. 3. Amphipathicity and sequence conservation of the peptide-binding site. A, space-filling model of 14-3-3 with residues defining the amphipathic groove colored by side chain type: hydrophobic (green), polar (dark gray), acidic (red), and basic (blue). The pS-Raf-259 peptide backbone with its phosphoserine side chain is shown in yellow. Asp or Glu substitutions leading to reduced Raf binding3 (19) are marked with * (strong effect) or with ± (weak effect). B, the concave inner surface of 14-3-3 with residues invariant across 30 eukaryotic species in red (see also Table II). The R18 peptide is shown in green. None of the residues solvent-exposed on the rear, convex surface are invariant (not shown). C, close-up view of residues from helices 3, 5, 7, and 9 forming the amphipathic groove. All residues exposed in the groove are labeled except Gly53 and Gly169. The viewing orientation and coloring scheme are as in A. Residues boxed in solid or dashed lines correspond to those marked in A by * or ±, respectively. D, schematic of a 14-3-3 dimer with helices as cylinders showing bound Raf peptides with their phosphoserine side chains. The two peptides are oriented in an antiparallel fashion. The view is rotated by 90 ° around a horizontal axis compared with A-C, so that the dyad axis lies vertically in the plane of the page. The figure was produced with Molscript (32) and Raster3D (31).